Starter drive for internal combustion engines



Dec. 1, 1936. Y. sEKELLA STARTER DRIVE FOR INTERNAL COMBUSTION ENGINESFiled June 21, 19:55

' Patented Dec. 1, 1936 STARTER DRIVE 'roR m'rnnnan COMBUSTIONENGINESYouston Sekella, Elmira, Y., assignorto Eclipse Machine Company, Elmira,"N. Y. a corporation of New York Application June 21, 1935, Serial No,27,754 9 Claims. (01. 74-17).

The present invention relates to a starter drive for internal combustionengines of the type whichautomatically engages and drives a member ofthe engine to be started, and more particularly -to a yieldingconnection incorporated in such drive.

It is an object of the presentinvention to pro vide a novel starterdrive which is small 1 and compact although powerful and efiicient inoperation.

It is another object to provide such a device which is balanced bothstatically and dynamically and retains such balance during use.

It is a further object to providesuch a device which incorporates ayielding driving connection in the form of a spring with novelconnecting and supporting structure therefor. 1

It is another object to provide such a device 20' which is arranged toenclose and compress the spring prior to the application of torquethereto;

It is another object to provide such a device in which theconvolutions-of the spring are radially flattened and maybe caused toengage frictionally for the transmission of torque.

Further objects and advantages will be ap-' parent from the followingdescription taken in connection with the accompanying drawing in which:a

Fig. 1 is a side view partly in section of a preferred embodiment of theinvention; 5

Fig. 2 is a detail in side elevation showing the attachment of thespring;

Fig. 3 is an extended view of certain of the parts of the drive,including the yielding driving connection, showing the partsdisassembled but in their proper relative positions; and

Fig. 4 is a vertical section taken substantially Referring first to Fig.1 of the drawing, there is illustrated a power shaft l which maybe theextended armature shaft of a starting motor, not shown, said shaft beingjournalled at 2 adjacent a member such as a flywheel gear 3 of an engineto be'started. A sleeve 4 is rigidly mounted on the power shaft I bysuitable means such as a key 5 (Fig. 4), and a locating pin or-screw 6,

one end of said sleeve being enlarged to form 'adriving'head 1 which isprovided with flattened surfaces 8 and 9 for a'portion of its lengthleaving shoulders 1| andlladjacent'the end thereof; A hollow screw shaft13 is freely journalled on the sleeve 4 and a nut I4 is threaded thereonand connected by a barrel 15' to an engine driving member in the form ofa pinion l6 freely jourand anchoring members in the form of discs v2!nailed on the power shaft l in position to be moved longitudinally intoandout of mesh with the engine flywheelgear 3. Anabutment in the form ofa stop nut I! is rigidly fixed on the inner end of the sleeve 4 andlimits the longitudinal 5 movement of the screw shaft l3 and. nut I 4 inthe direction toward the engine member, an antifriction washer l8 beingpreferably mounted on the sleeve adjacent the stop nut 11.

The threads on the shaft I3 are preferably cut away toform a smoothportion l9 at the idle pc sition of the nut l4 whereby when the pinionl6 is 'demeshed, the nut may run oil the endsof said threads, thepinion, barrel and'nut being thus permittedto rotate freely until theirmo-' 15 in the barrel betweenthe pinion and stop nut llin ordertoinsure-initial engagement of the nut M with the threads on the shaft l3.A light springr22 is also; provided between the-abutment Il' and'nut Hfor yieldingly preventing-drifting of the pinion toward the'engine gear;According to, the present invention, a yielding drivingiconnection isprovided between the driving, head 1 on the sleeve 4 and a similarlyformed driven head 23 on the screw shaft I3 in the form of a torsionspring 2.4 having spaced radiallyflattened convolutions terminating inoutwardly turned hooks 25 and 26 (Fig.. 3). Supporting and 28 areslidably and 'non-rotatably mounted on the driving and driven headsrespectively,.r otation of the discson'the heads being prevented I by ena ement of the flat walls 29 and 3| of. the openings in ,the discs withvthe corresponding flat surfaces 8 and 9 of said heads. The .discs areprovided with notches 32 and 33 extending radially inward from theirperipheries and. having rounded shouldersjas best seen at 34in Fig, 2

conforming to theshape of thehooks 25 and 26 40 and forming an anchoragetherefor .S aid discs are preferably formed on their opposed sides. withh'elical surfaces ,of substantially the same pitch as the spring,thusjormin'g seats for, the end convolutions thereof. as ,clearlyillustrated in Fig. 2. The end convolutions of the spring are preferablywound down to conform to the surfaces of the driving'and driven headsin. order to make the'anchoragerigidand hold the f'sprin'g concentric. fi

Suitable thrust and friction ,washers are inter.- posed between thedriving'he'ad dand drive'n' head .23, and 'heretake thefo'rmof a pairrofmetal 5 a washers as and as; witha fiberwasher 31"1nter posed therebetween.

, 'Ijhe locating pin 6 is preferably positioned'in the driving head 4beneath the normal position of the anchoring disc 21 whereby accidentalloosening of the pin is effectively prevented. Re-

moval thereof is, however, readily accomplished by moving the disc 21toward the driven head against the compression of thespring 24 until thehead of the pin is exposed.

In the operation of this device, rotation of the power shaft l by thestarting motor causes the sleeve 4 to rotate and carry with it theanchoring disc 21. This rotation is transmitted through the spring 24 tothedisc 28 on the screw shaft l3 which is thus caused to rotate andthereby translate the nut threaded thereon with the barrel l5 and pinionIt to mesh the pinion with the engine gear 3. When the meshing action iscompleted, the nut l4 engages the thrust washer l8 of abutment llwhereby further translation of the nut is prevented. The screw shaft I3is then forced back, compressing the spring 24 until the driven head 23engages the thrust washer 35. Cranking torque is thereupon transmittedto the screw shaft through the frictional driving action of the washers35, 36,31 and through the torsiona-l windup of the spring 24. It will beunderstood that since the spring is compressed substantially solidbefore the cranking'loadis assunied thereby, escape of the hooks 26 fromthe slots 32, 33 of the prevented. M

It is within the purview of the invention to omit the thrust washers 35,36 and 31 and allow the end thrust of the screw shaft l3 to be takenentirely by the spring 24 whereby the convolutions thereof are pressedtogether and transmit anchoring discs is effectively A cranking torquefrictionally. It has been found,

however, that the frictional transmission of torque is more easilycontrolled by means of the thrust washers.v

when the engine starts, the overrunning of the engine flywheel 3accelerates the pinion and its connected parts, causing the nut l4 tooverrun the screw shaft and return to its idle position,

thus permitting the screw shaft to return to its normal position underthe expansive'effect of the spring 24.

It will be understood that various changes-may be made in the design andarrangement of the parts of this device without departing from thespirit of the invention as defined in. the claims appended .hereto. i

What is claimed is: 1. In'a'starter drive a power shaft, a pinion freelyjournalled thereon for longitudinal movementinto and out of engagementwith a member 'ofan engine to be started, a screw shaft rotatablymounted on the power shaft, a nut threaded on said screw shaft andrigidly connected to the pinion, a stop member flxed onthe power shaftdefining the normal position of the screw shaft and the operativeposition of'the nut, and means for rotating the screw shaft from thepower shaft including a torsion spring and a pair of anchoring andsupporting members non-rotatably concomponent of. the driving forcestransmitted througlr the screw and nut, thus compressing the a aoaasao tv t 4 spring between the anchoring and supporting engagement of themembers. i

a 2. In a starter, drivea power shaft, ajpinion freely journalledthereon for longitudinal move-' ment into and out of engagement withamember of an engine to be started, a screw shaft slidably and rotatablymounted on the power shaft, a nut threaded on said screw shaft andrigidly connected to the pinion, an abutment for said nut fixed on saidpower shaft between the screw shaft and pinion, and means for rotatingthe screw convolutions of said spring conforming'to said I seats andhaving outwardly turned ends engag-. .ing in said recesses, said nutbeing arranged to move longitudinally to mesh the pinion with. theengine member upo rotation of the screw shaft, ut against the abutmentcausing the screw shaft to movebackward and compress the spring,preventing escape of the outwardlytu'rned ends 'of the spring from the$65863 in the anchoring andsupporting mem- 3. In a starter drive a powershaft, a member adapted to engage and drive a member of an engine to bestarted, and a driving connection therebetween includinga torsion springhaving radially flattened normally spaced convolutions andlongitudinally outwardly turned ends, an-

choringand supporting members connected respectively tothe power shaftand engine driving member andhaving helical seals to receive and supportthe terminal convolutions of the spring,

convolutions of the spring are uniformly compressed while beingprevented from weaving or tipping over.

4. In a starter drive a; torsionispring having radially flattenednormally spaced convolutions, anchoring discs for the spring havinghelical surfaces forming seats for substantially the entire endconvolutions thereof, and means forcing the discs together to compressthe spring therebetween prior to the application of cranking torquethereto.

5. In a starter drive a torsion spring having radially flattenednormally spaced convolutions terminating in longitudinally extendinghooks, a pair of anchoring discs for the spring having recesses forreceiving said hooks and helical surfaces conforming to theend'convolutions of the spring, and means for compressing the springbetween said discs concomitantly with the transmission of torquetherethrough during the crank,- ing operation.

6. In a starter drive a torsion spring having radially flattenednormally spaced convolutions terminating in substantially quadrantallongitudinally extending hooks, a pair of anchoring discs-for the springhaving helical surfaces forming seats for-the end convolutions thereofand peripheral recesses for receiving-said books, the driving sides -ofsaid recesses being. defined by curved shoulders conforming to thecurvature of thehooks, and means responsive to cranking torquetransmitted therethrough for-compressing said spring between the discs.

"I. In a starter drive for internal combustion engines a power shaft, apinion journalled thereon for longitudinal movement into and out ofengagement with a member of an engine to be started, means for actuatingthe pinion from the shaft including a torsion spring, a driving head;

non-rotatably mounted on the driving head, and

means for locating thedriving head on the shaft, said anchoring memberbeing arranged to normally surround and retain said locating means, andbeing movable along the shaft against the compression of the spring tofree the locating means. I

9. In a starter drive 'for internal combustion engines a power shaft, apinion journalled thereon for longitudinal movement into and out ofengagement with a member of an engine to be started, means for actuatingthe pinion from the shaft including a torsion spring, a driving head, ananchoring disc member for the spring nonrotatably mounted on the drivinghead, and a locating pin traversing the driving head and entering theshaft, said anchoring disc being yieldably held by the longitudinalpressure of the spring in position to cover and retain said pin.

YOUSTON SEKEILA. 20

